Mary Allen
Clawed frogs are very adaptable. They can survive in salty water for a short time and can go a few months without food.
Characteristics
What do clawed frogs look like?
Clawed frogs are amphibians and breathe with their lungs. They basically look like our frogs. They grow about 11 to 13 centimeters tall. The females of the clawed frogs are usually significantly larger than the males and have a small extension on the rear part that looks like a little tail. Their skin is so smooth and slippery that you can hardly hold them in your hand.
The clawed frogs got their name from a special feature: They have large black claws on the three inner toes of their feet. The Latin name Xenopus also refers to this feature: it means “strange foot”. The feet of the hind legs are webbed, while those of the front legs are not.
The eyes of the clawed frog are located quite high on the head. The abdomen and the undersides of the legs are mostly colored beige. However, the animals can also change their color and turn lighter or darker. This is ensured by special pigments in the skin cells. This discoloration allows them to better adapt to their environment.
Where do clawed frogs live?
Clawed frogs come from Africa and live there in the regions south of the Sahara. However, because they were formerly used in medical laboratories for tests and later released into nature, they also live in the American Southwest today. Animals have also been discovered in river canals in the Netherlands.
Unlike our native real frogs, clawed frogs do not live partly in water and partly on land, but are only found in freshwater. They live in flowing and standing water such as streams, ponds, and small lakes with muddy bottoms. They only leave the water in an emergency, for example when it dries up or they can’t find any more food. When they have to trek overland, they cover just 200 meters in two days.
What types of clawed frogs are there?
Clawed frogs belong to the order of the frogs and there to the suborder of the tongueless. There are four genera of them: clawed frogs, honeycomb toads, and two different genera of dwarf clawed frogs. The term “tongueless” comes from the fact that these frogs actually don’t have a tongue.
They are also related to our native frogs such as the common frog. But these belong to the order of real frogs. There are about 18 different species of clawed frogs, but even experts find it difficult to distinguish between them. The best-known clawed frog is Xenopus laevis.
How old do clawed frogs get?
Clawed frogs can get very old: they live for around 20 to 30 years.
Behave
How do clawed frogs live?
Clawed frogs only become active in the evening and at night. Then they search the bottom of their water for food. They have developed a special technique: They dig up the ground with their front legs by moving their hands to their mouths. Clawed frogs are perfectly adapted to life in the water. With their long, powerful hind legs and large webbed toes, they can swim very well – even backward. Clawed frogs cannot see and smell very well.
But they have another organ that helps them to orientate themselves in the water: it is the so-called lateral line organ, which runs on both sides of the body. It has up to 500 sensory hairs. With this organ, clawed frogs perceive even the smallest movements, for example of prey.
Clawed frogs became famous because it was discovered in the first half of the last century that they can be used for pregnancy tests: If you inject the urine of a pregnant woman under the skin of a female clawed frog, she will lay eggs within two days. If the woman is not pregnant, this does not happen. However, after chemical tests were later developed, clawed frogs are no longer used for this purpose in laboratories.
The clawed frog Xenopus laevis is the clawed frog most commonly kept in our aquariums because the animals are very adaptable. It has been discovered that although clawed frogs come from freshwater, they can even survive in salty water. However, this is only possible for a limited time. They can also adapt to extreme temperatures, even surviving temperatures as low as 0°C or 30°C for short periods. Clawed frogs living in North America even hibernate under the ice.
Friends and foes of the clawed frog
Cormorants and reptiles such as snakes can become dangerous to the clawed frogs. With the poison that secretes the skin of clawed frogs, however, they can often scare off predators. In some regions of Africa, clawed frogs have also been eaten by humans.
How do clawed frogs reproduce?
The mating season of clawed frogs in Africa lasts over ten months. That means they mate almost all year round. When the males are in the mood for mating, they get dark spots on the inside of their arms. They are small suction cups that the males use to hold on to the females when they clutch them during mating.
The female then lays up to 2000 eggs. The eggs sink to the bottom or stick to aquatic plants. Small tadpoles then hatch from the eggs, just like our frogs. They have a tail and breathe with gills. Gradually they transform into little frogs. At around 22 to 26 months, clawed frogs become sexually mature.
How do clawed frogs communicate?
Clawed frogs have very peculiar calls: they just emit a soft ticking sound.